Defeat censorship with cryptography

Okay, it's time for a tutorial. Cryptography lesson 1! This is exciting guys.

So the first method of encryption that we are going to learn today is a very basic one. You've probably learned about it in primary school or high school. It's called the Caesar Cipher. This is a very easy way to write hidden messages, especially for beginners.

It's a substitution cipher where each letter in the plaintext is shifted a certain number of places down or up the alphabet. Here's a step-by-step guide:
Caesar Cipher:

Choose a Shift Value (Key): Decide on a number to shift the letters. This is your key. For example, a shift of 3 means that 'A' becomes 'D,' 'B' becomes 'E,' and so on.

Write Your Message: Start with your plaintext message, the message you want to encrypt.

Shift the Letters: Replace each letter in your message with the letter that is a fixed number of positions down or up the alphabet.
For example, with a shift of 3:
Plain: ABCDEFGHIJKLMNOPQRSTUVWXYZ
Cipher: DEFGHIJKLMNOPQRSTUVWXYZABC

Encrypt Your Message: Replace each letter in your message with the corresponding shifted letter. Leave non-alphabetic characters (like spaces or punctuation) unchanged.
Example: "HELLO" with a shift of 3 becomes "KHOOR."

Decrypting: If you want to share the hidden message, the recipient needs to know the shift value. They can then shift the letters back to reveal the original message.

Example:

Let's use a shift of 3 with the message "HELLO."

Plain: H E L L O
Cipher: K H O O R

So, "HELLO" becomes "KHOOR" when encrypted with a Caesar Cipher and a shift of 3.


Although this is a fun and basic way to encrypt messages, it's not very secure. Your code can easily be cracked with method's such as brute force or frequency analysis. Basically, if someone is patient enough to cycle through every one of the 25 shift value keys (start with a different letter of the alphabet), they will eventually find the one needed to decipher your message.

If you want some solid lolz, decipher this!

Shift key 10 (a-->k)

Gri dbyvv Jyvk kxn D4C wocckqo lykbnc? Okci Jyvk sc dro vyv myg drkd tecd uoozc yx qsfsxq!

Govv, drbyeqr k vsddvo cymskv oxqsxoobsxq, S gkc klvo dy zkcc dro pybew'c nopoxmoc kxn boqscdob kx kmmyexd exnob k pkuo kfkdkb (Wyxsaeo). Xyg dro pex loqsxc!
Iye coo, moxcybsxq dro pybew rkcx'd kmdekvvi nyxo kxidrsxq dy nodob kxiyxo pbyw dbyvvsxq kxn wkusxq k wymuobi yp Jyvk kxn dro D4C.
Sd'c yxvi cdspvon dro qbygdr yp dro D4C mywwexsdi, lomkeco xog wowlobc rkfo dy tewz drbyeqr vsdobkv ryyzc tecd dy qod kx kmmyexd.

Led drkd'c tecd sd. Sd gkc xofob klyed dro dbyvvsxq, gkc sd? Dbyvvsxq gkc tecd kx ohmeco dy myfob ez Jyvk'c bokv sxdoxdsyxc.
Cro sc k mevd voknob kxn cro gkxdc zoyzvo dy vsddobkvvi vsmu dro crsd yed yp rob kccryvo lopybo droi kbo kvvygon dy zycd. Cro gkxdc dy lo gybcrszon, tecd vsuo Wkhsxo pbyw dro Tyi yp Ckdkx.
Cro nyocx'd bokvvi mkbo klyed Ckdkxscw. Cro tecd mkboc klyed qod cywo zbksco kxn knybkdsyx pbyw k pog vyikv pyvvygobc.

Jyvk sc kvcy vkji. Cro sc zobpomdvi myxdoxd dy csd lkmu kxn gkdmr ydrobc ny dro gybu. Csxmo S vopd dro wsxscdbi, cro rkcx'd nyxo kxidrsxq dy nofovyz dro golcsdo.
Govv, xyg go kbo qysxq dy rkfo cywo pex kxn coo ryg wkxi vyvj drsc vyv myg rkc vopd dy qsfo! Drsc sc qysxq dy lo pex.
Kxn nyx'd qod wo gbyxq, S nyx'd rkfo kxidrsxq kqksxcd Jyvk. Sd'c tecd pex dy dkuo dro zscc yed yp zoyzvo gry kbo dyy cobsyec klyed vspo.
Go kbo qysxq dy ohzvysd wkxi ydrob pybewc kxn cymskv wonsk zvkdpybwc yx yeb tyebxoi!

Actually I just thought of the perfect Place! This is going to be fun. Stay tuned for updates.

LMAO forum.becomealivinggod.com/t/hello-just-introducing-myself/184540/4?u=radioactiveneckbeard

Now that you saw some working examples of how to defeat censorship using cryptography, it's time for:

Cryptography lesson 4:

The affine cipher is a type of monoalphabetic substitution cipher, where each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter. In the case of the affine cipher, the encryption function is of the form E(x)=(ax+b)mod  mE(x)=(ax+b)modm, where:

xx is the numeric value of the plaintext letter,
aa and bb are the key parameters,
mm is the size of the alphabet.

The values of aa and bb must be chosen such that aa and mm are coprime (they have no common factors other than 1), ensuring that the encryption and decryption processes are reversible.

The decryption function is of the form D(y)=a−1(y−b)mod  mD(y)=a−1(y−b)modm, where a−1a−1 is the modular multiplicative inverse of aa modulo mm. It's important to note that a−1a−1 exists only if aa and mm are coprime.

Here's a step-by-step explanation of the encryption and decryption processes:
Encryption:

Assign numeric values to the letters: Convert each letter of the plaintext to its numeric equivalent, typically using the position in the alphabet (e.g., A=0, B=1, ..., Z=25).

Apply the encryption function: For each numeric value xx, compute E(x)=(ax+b)mod  mE(x)=(ax+b)modm to get the ciphertext numeric value.

Convert back to letters: Convert the numeric values obtained in step 2 back to letters using the reverse of the mapping used in step 1.

Decryption:

Assign numeric values to the letters: Convert each letter of the ciphertext to its numeric equivalent.

Calculate the modular multiplicative inverse: Calculate the modular multiplicative inverse a−1a−1 of the key aa modulo mm. This step is possible only if aa and mm are coprime.

Apply the decryption function: For each numeric value yy, compute D(y)=a−1(y−b)mod  mD(y)=a−1(y−b)modm to get the plaintext numeric value.

Convert back to letters: Convert the numeric values obtained in step 3 back to letters using the reverse of the mapping used in the encryption process.

The affine cipher provides a way to encrypt and decrypt messages using a relatively simple mathematical formula, but its security is limited compared to more complex ciphers. The key parameters aa and bb play a crucial role in determining the strength of the cipher, and an inappropriate choice can lead to vulnerabilities.